Well drilling impact tool and apparatus



Sept. 10, 1968 c. J. CARR ETAL WELL DRILLING IMPACT TCQL AND APPARATUS 3 Sheets-Sheet 1 Filed Aug. 11, 1966 fi I1 I 1 -1 (bar/es Dad/e3 Hughes Sept. 10, 1968 c. J. CARR ETAL.

WELL DRILLING IMPACT TOOL AND APPARATUS 3 Sheets-Sheet 2 Filed Aug. 11, 1966 Char/es J Carr /ey ag/ves 9 .ISW/en zors .M, .Dud

fittorner/ Sept. 10, 1968 c. J. CARR ETAL WELL DRILLING IMPACT TOOL AND APPARATUS 3 Sheets-Sheet 5 Filed Aug. 11, 1966 7% y 3% an w W Z M 2 h p a M 7 z United States Patent 3,400,772 WELL DRILLING IMPACT TOOL AND APPARATUS Charles J. Carr, Anaheim, and Marion Dudley Hughes, 'Long Beach, Calif. (both of 1111 Security Bldg., Long Beach, Calif. 90802) Filed Aug. 11, 1966, Ser. No. 571,830 12 Claims. (Cl. 175-92) ABSTRACT OF THE DISCLOSURE A combination rotary and impact tool and apparatus for drilling wells including, an elongate string of fluid conducting drill pipe extending downwardly into a well structure, an elongate fluid conducting rotary drive axially extensible sub fixed to the lower end of the string of drill pipe, an elongate fluid conducting drill collar fixed to and depending from the sub, an elongate fluid conducting jack tool fixed to and depending from the lower end of the drill collar and a formation engaging bit fixed to the lower end of the jack tool, said jack tool being driven by fluid conducted through the apparatus and adapted to elevate the drill collar relative to the bit and drill pipe string, to permit the drill collar to drop and to stop downward movement of the drill collar to direct impact forces onto and through the bit.

This invention has to do with a well drilling apparatus and is more particularly concerned with a tool and apparatus for drilling oil wells by rotary and/ or percussion methods, that is, by rotating a bit into the earth formation and/ or driving said bit into the formation by axially directed impact forces onto and through the bit.

It is an object of the invention to provide a tool and/or apparatus adapted to intermittently impose axially downwardly directed impact forces onto and through a bit at the bottom of a well hole to establish a new hole, without requiring raising and lowering of the bit from engagement on the bottom of the hole and without requiring raising and lowering of the drill string with which the bit is related by and with means at the top of the well.

Yet another object of the invention is to provide a tool and apparatus of the character referred to which is such that the bit can be provided with a laterally and downwardly disposed nozzle and is such that it can be rotatively oriented in the bore to direct a jet or stream of circulating fluid towards the bottom and a predetermined side of the hole to hydraulically reduce the formation in advance of and to one side of the bit, whereby the direction in which the bit advances in the formation can be varied and controlled.

Still another object of this invention is to provide a novel roller bit wherein the roller cutters are circumferentially spaced and are of such construction and relationship that the bit, when stopped against rotation and upon application of axially downwardly directed weight and impact forces, tips, reduces the formation at one side of the bottom of the bit and causes the bit to drift laterally in the formation towards that said one side.

Still another object of this invention is to provide a tri-cone roller bit having one roller cone, that is smaller in diameter than the other cones and which is such that when the bit is stopped in a predetermined rotative position in the hole and percussion drilling is commenced by directing impact forces axially into and through the bit, the bit will drift laterally in the direction opposite the side of the bit on which the small diameter cone is lo cated.

Another object of our invention is to provide an apparatus of the character referred to which involves a bit,

3,409,772 Patented Sept. 10, 1968 a string of drill collar of predetermined mass above the bit, an axially shiftable lost-motion sub at the upper end of the drill collar string, a drill pipe string extending upwardly from the sub and a hydraulically operated jack tool between the bit and collar string and operable to intermittently elevate the collar string relative to the bit and drill pipe string and to release and permit said collar string to drop and to drive and hammer the bit into the formation.

Another object of the invention is to provide a jack tool of the character referred to which has a novel striker means and novel valving means.

The foregoing and other objects and features of our invention will be fully understood from the following detailed description of a typical preferred form and embodiment of our invention, throughout which description reference is made to the accompanying drawings in which:

FIG. 1 is an elevational view of our apparatus arranged in a well structure;

FIG. 2 is an enlarged, sectional view taken substantially as indicated by line 22 on FIG. 1;

FIG. 3 is an enlarged sectional view taken as indicated by line 3-3 on FIG. 1;

FIG. 4 is a view taken as indicated by line 44 on FIG. 1;

FIG. 5 is an enlarged detailed sectional View of a portion of the structure shown in FIG. 2 with parts shown in a different position;

FIG. 6 is a sectional view taken as: indicated by line 6-6 on FIG. 5;

FIG. 7 is a sectional view taken as indicated by line 7-7 on FIG. 5;

FIG. 8 is an enlarged detailed sectional view of a portion of the structure shown in FIG. 2 with parts shown in another position;

FIG. 9 is a sectional view taken as indicated by line 9-9 on FIG. 3; and,

FIG. 10 and FIG. 11 are sectional views taken as indicated by line 10-10 and lines 11-1]l on FIG. 8.

The apparatus A that we provide and which is illustrated throughout the drawings, is adapted to be engaged in a well bore or hole W entering the earths formation F and is operable to make or establish new hole in the formation. The apparatus A includes generally a bit B arranged in the well hole to occur at the bottom thereof, a jack tool I coupled with and projecting upwardly from the bit B, a string of drill collar C fixed to and extending upwardly from the jack tool I and hereinafter referred to as the collar, a lost motion sub S fixed to and we tending upwardly from the collar and a string of drill pipe P, hereinafter referred to as the drill pipe, fixed to the sub S to extend upwardly therefrom and to the top ofthe well.

The upper end of the drill pipe P is coupled with a rotary table, swivel, fluid circulating pump and other surface equipment commonly associated with and employed in rotary drilling rigs. Since the above referred to surface equipment can vary widely in form and construction, without affecting the novelty of this invention and is wellknown to those familiar with the art to which this invention relates, we will not illustrate such equipment and will not burden this disclosure with further description thereof.

The bit B can be a conventional roller bit such as is commonly employed in rotary drilling operations, or, as is illustrated, can be a special bit of unique design. The unique and special bit B illustrated in the drawings is similar in general form and construction with a conventional tri-cone roller bit, except that one of the three cones 10, 11 and 12, for example, the roller cone 10, is smaller in diameter than the cones 11 and 12 and is arranged so that its lowermost longitudinal side portion occurs in spaced relationship above the lowermost longitudinal side portions of the cones 11 and 12.

The small diameter roller cone is provided to facilitate advancing the bit into the formation by percussion methods, that is, by imparting sharp, axially downwardly directed forces onto and through the bit, without rotating the bit and to, at the same time, change the direction in which the well hole is advanced in the formation F.

By arranging the bit B in the bottom of the well hole W, with the roller cone 10 thereof at that side of the hole opposite the direction in which it is desired to cause the bit to drift, and to thereby deviate the direction in which the new hole is established, and by urging the bit downwardly by the weight of the structure above it and by axially downwardly directed impact forces, the bit will tip towards the side of the hole at which the cone 10 occurs and the structure which carries the bit and projects upwardly therefrom tips and leans over towards that side of the hole. With the bit and its related structure thus tipped, it will be apparent that the forces transmitted through the bit are directed in that direction in which it is desired to direct the bit and the roller cones 11 and 12 tend to reduce the formation in advance of the cone 1t pitching or inclining the bottom of the hole whereby the bit will tend to skid or slide laterally in the desired direca :axially directed forces to establish new hole by percussion method.

In light of the above, it will be apparent that the bit B is in fact an improved peg-leg type roller bit and may therefore be referred to as a peg-leg bit.

In addition to the above, the bit B is provided with a downwardly and slightly laterally outwardly inclined nozzle 13 communicating with .a fluid passage 14 entering and extending through the upwardly projecting threaded pin portion 15 of the bit. The nozzle is adapted to direct a jet of circulating fluid downwardly and laterally outwardly towards the bottom and one side of the hole W to reduce the formation hydraulically and to clean the formation in advance of the bit. The nozzle 13 is arranged at the side of the bit between the roller cones 11 and 12 and diametrically opposite the cone 10, whereby the formation at the side of the bit into which it is desired that the bit drift, for the purpose of deviating the direction in which the new hole is established, is hydraulically reduced, when the bit is stopped in the above-noted predetermined rotative position and percussion drilling operations are being carried out.

The above-noted hydraulic reduction action afforded by the nozzle in the bit enhances the ability of the bit to drift laterally in a predetermined direction. The effectiveness of hydraulic reduction of earth formation by jet action is well established and is widely practiced. Typical of such reduction of formation and for the purpose of deviating the direction in which a well bore is advanced in a formation is that method of making hole, commonly referred to as spudding and which is taught in U.S. Patent No. 2,873,092, issued to R. P. Dwyer, on Feb. 10, 1959.

It is to be noted, however, that in the art of spudding, referred to above, the bit, with the nozzle therein and from which the formation reducing jet of circulating fluid issues. is raised and lowered in the bore hole to drive the bit forwardly and the jet is therefore moved into and out of eifective range from the formation being acted upon. As a result, the entire operation is not too effective or eificient. Further, in spudding operations, the entire drilling string must be raised and lowered to gain the desired effect.

In the instant case, when our apparatus is in use and as will be apparent from the following, the bit B remains on the bottom of the well hole W and impact forces are directed upon and through the bit. The entire drill string n ed not be elevated and lowered and the nozzle means, at all times, is in effective and efiicient range of the formation it is sought to hydraulically reduce.

Since other details of construction and operation of the bit B are standard or conventional and can vary widely without departing from the spirit of our invention, we will not burden this application with further detailed description thereof.

The drill collar C, in accordance with common practice, has a central longitudinal flow passage 16 and is provided with threaded pins 17 and 18 in its upper and lower ends. In practice, the drill collar is made up of a number of stands and drill collar pipe sections to provide a predetermined weight or mass for operation of the jack tool I, as will hereinafter be described.

The lost motion sub S arranged between the collar C and the lower end of the drill pipe P is shown as including a pair of telescopically related tube sections 20 and 21. The inner section 20 has its upper end connected with the lower end of the drill pipe P, is provided with splines 22 at its lower end portion and carries a depending extension 23 with an enlarged head 24 at its lower terminal end. The outer section 21 has a lower downwardly opening bore 25 in which the head 24 is slidably engaged. The bore 25 terminates at a flat downwardly disposed stop shoulder 26 against which the head stops upon axial upwardly shifting of the section 20. The lower end of the bore 25 is closed by a box plug 27 in which the pin 17 of the collar C is engaged and against which the head 24 stops upon downward shifting of the section 20. The section 21 is further provided with a central opening 28 through which the extension 23 projects and an upwardly opening splined bore 29 in which the lower splined portion of the section 20 is slidably engaged for free axial shifting and against relative rotative shifting of the sections. The upper end of the bore 29 is closed by a plug 30 through which the upper portion of the section 20 is slidably engaged.

The upper section 20, extension 23 and head 24 have a central, longitudinal flow passage to conduct fluid from the drill pipe P downwardly through the sub and into the collar C.

The head 24 carries suitable sealing means 31 to seal with the bore 25.

With the sub S set forth above, it will be apparent that the collar can be freely elevated and lowered relative to the drill pipe string, as circumstances require, and so that rotary driving engagement between the collar C and pipe P is maintained at all times.

It will also be apparent that relative axial shifting of the sections of the sub is limited and that upon upward shifting of the pipe P and section 20 of the sub, beyond a predetermined distance relative to the section 21, the section 21 and all the other structures directly related thereto, is elevated, thereby making it possible to pull the apparatus from the well W.

The sub 8 illustrated and described above is only typical of one of several available lost motion, knocker and/ or bumper sub constructions provided by the prior art which can be employed in establishing the apparatus A of our invention. Accordingly, novelty of this invention is not dependent upon the particular lost motion sub construction herein disclosed.

The hydraulic jack tool I that we provide is operable to intermittently jack up or elevate the collar C relative to the bit B and drill pipe P and to release and permit the collar to drop and move downwardly relative to the pipe P and bit B in such a manner as to impart impact forces onto and through the bit to elfect percussion drilling and without requiring the bit to be moved up and out of engagement with the formation and without requiring the drill pipe P to be elevated and lowered. The tool I is operated by circulating fluid conducted through the apparatus, under pressure. The relative shifting of the parts is made possible by the provision of the lost motion sub S.

The jack tool I includes alower assembly L connected with the 'bit B, an upper assembly U connected with the collar C, coupling means M between the assemblies to establish rotary driving engagement and free axial shifting therebetween, striker means S to effect downward impact forces upon downward relative movement of the assemblies, drive means D to drive the upper assembly vertically relative to the lower assembly, valve means V controlling the operation of the drive means and actuator means E for the valve means.

The lower assembly L includes a pin and box member 40 having a threaded box to receive the pin 15 of the bit B, an upwardly projecting threaded pin 41 and a central flow passage 42 communicating with the flow passage 14 in the bit, an elongate cylindrical lower section or cylinder 43 with a central, longitudinal, cylindrical, piston bore 44 threadedly engaged on the pin 41 to project upwardly therefrom and having a plurality of circumferentially spaced, radially outwardly opening exhaust ports 45 at its upper end; a collar 46 with a central wash pipe receiving opening 47 and downwardly and upwardly projecting threaded pins 48 and 49 arranged at the upper end of the lower sections 43 with the pin 48 threadedly engaged therein and closing the upper end of the cylinder bore and an upper elongate cylindrical section or barrel 50 with a fiat, upwardly disposed upper end defining a stop surface 51, a central longitudinal splined bore 52 and a thread box 53 entering its lower end and in which the pin 49 of the collar 46 is engaged.

The upper assembly U includes an elongate splined mandrel with a central flow passage 61 slidably engaged in the splined bore 52, an enlarged head 62 -at the upper end of the mandrel defining a downwardly disposed striker surface 63 to oppose and engage the stop surface 51 and having an upwardly opening box 64 in which the pin 18 of the collar C is engaged.

The mandrel is further provided with an enlarged piston bore 65 of limited longitudinal extent entering its lower end, which bore is closed by an annular stop ring 66 threadedly engaged into the lower end of said bore.

In practice, the lower end of the central flow passage 61 is provided with a flow bean type stop ring 67 to increase the area of the downwardly disposed bottom surface 71 of the bore.

The assembly U further includes an annular pump down or servo-piston 70 engaged in the piston bore 65 and shiftable between and engageable with the downwardly disposed bottom 71 of said bore and the stop ring 66; an elongate vertical wash pipe 72 with its upper end threadedly engaged in the servo-piston to depend therefrom, through the opening 47 in the assembly L and into the cylinder bore 44 and a drive piston 76 threadedly engaged on the lower end of the wash pipe and shiftable axially in the cylinder bore.

The servo or pump down piston 70 is provided with suitable sealing means 73, such as O-rings, to seal with the piston bore 65 and the stop ring 66 is provided with vertical drain ports 79 to establish communication between the bore 65, below the piston 70 and the bore 52, whereby fluid in the bore 65, below the servo-piston is not trapped in such a manner as to create a fluid lock and prevent axial shifting in the servo-piston relative to the mandrel. g

It will be apparent from the foregoing that the drive piston 76 is coupled with the mandrel, by means of the servo-piston 70 for limited axial shifting relative thereto and that fluid pressure acting upon the top of the servopiston tends to urge the drive piston down relative to the mandrel.

It will be further apparent that the stop ring 66 cooperates to limit downward shifting of the wash pipe and drive piston relative to the mandrel and axial separation of the mandrel and wash pipe when the apparatus is elevated, as for the purpose of pulling it from the well.

The drive piston 76 is of unique design and has a primary lower portion 77 which suitably. slidably engages the cylinder bore and carries suitable sealing means 78 (O-rings), a central neck portion 79 of reduced diameter and an enlarged upper head portion 80. The lower and upper portions cooperate with the central portion to define an annular flow chamber X about the piston and between the ends thereof. The lower portion 77 is provided with a plurality of circumferentially spaced, vertically extending flow ports 81 communicating between r the flow chamber X and the cylinder bore below the piston. The ports 81 are provided with suitable valve seats 82 at its lower ends.

The upper portion of the piston 76 is provided with valve rod guide openings 83 in axial alignment with the ports 81 and circumferentially spaced radially outwardly opening, axially extending flow channels Y establishing communication between the chamber X and the cylinder bore above the piston.

In addition to the above, the piston 79 is provided with a central, upwardly opening box 84 in. which the lower end of the wash pipe is engaged and a central downwardly opening flow passage 85 which communicates with the wash pipe.

The wash pipe is provided with an annular stop collar 86 in spaced relationship above the drive piston, which collar is fixed to the pipe as by welding and establishes an upwardly disposed stop surface 87, which opposes and is adapted to engage and stop against the bottom of the collar 46 and limit upward movement of the upper assembly relative to the lower assembly and a lower spring stop surface 88. The collar 86 is also provided with guide pin openings 89 which occur in axial alignment with the openings 83 in the piston 7 6.

The valve means V that we provide include a valving member 90 related to each port 81 and shiftable vertically into and out of engagement with the seat 82 related to that port. Each valve member has an elongate, vertical operating stem 91 which projects freely upwardly through the port with which it is related and with sufficient clearance to provide for free flowing fluid upwardly through the port and into the chamber X, when the valve is open. The stems terminate above the lower portion of the piston, within the chamber X.

The actuating means E for the valves: include elongate, vertical operating rods 92 formed integrally with and projecting upwardly from the valve stem and through the guide openings in the upper portion of the piston and actuating pins 93 formed integrally with and projecting upwardly from the rods 92 and extending through the openings 89 in the stop collar 87 on the wash pipe.

The operating rods 92 are larger in diameter than the stems and pins and are provided with axially or vertically spaced radially outwardly opening grooves 94, which grooves are spaced apart a distance equal to the distance of travel of the valve member 90 between their fully open and fully closed positions.

The upper portion of the piston is provided with spring loaded latch means related to each rod 92, to releasably engage in the grooves 94 and releasably hold the rods and the valve in either their open or closed positions. In the instant case, we have, for the purposes of illustration, shown the lock means as spring loaded ball type means carried by suitable cups threadedly engaged in latch openings in the piston communicating with the openings 83.

It will be apparent that the latch means could be related to other structures, for example, the latch means could be related to the stop collar 86, without departing from the spirit of this invention.

The actuating means provided further includes a conpler ring 96 slidably engaged about the wash pipe to engage and stop against the tops of the several rods 92 and through which the pins 93 on the rods project and a compression spring 97 between the ring 96 and bottom surface 88 of the stop collar 37 to normally yieldingly urge the ring downwardly into stopped engagement with the top of the piston '76 and to that position where the valves are open. The spring 97 can, as illustrated, be arranged between the wash pipe and pins or about the exteriorof the pins, as desired. Further, a plurality of separate springs, each engaged about a pin, could be employed and still fall within the spirit of this invention.

The spring 97 is not sufliciently strong to overcome and release the latch means 95 when the construction is in the position shown in FIG. 8 of the drawings, but is such that when the lock means is otherwise released, the spring will urge the valve to its fully open position and the rods to that position shown in FIG. of the drawings, where the latch means again sets to hold the valves open.

It is found necessary to provide an actuating means such as set forth above so that when the valves are initially cracked open, they will not stop in a partially open position and so that when they are in their fully open position, the flow of fluid through the ports 81 and about the valve members 90 and stems 91 will not wash the valves up to their closed position and render the construction inoperative.

The upper ends of the pins 93 are flush with the top of the stop collar when the valves are down in their open position, as illustrated in FIG. 5 of the drawings, and

project upwardly from the collar when the valves are up in. the closed position and as illustrated in FIG. 8 of the drawings.

With the above relationship of parts, it will be apparent that when the valves are in their closed position and the piston 76 moves upwardly, the upper ends of. the pins first engage the top of the cylinder bore, that is, the bottom of the collar 56. Upon further upward shifting of the piston, the stopped pins and rods are shifted downwardly relative to the piston to release the latch means, Whereupon the spring 97 urges the valves to their fully open position.

It is to be noted that the stop collar 87 does not ordinarily stop against the collar 46 of the lower assembly, but only engages and stops against the collar 46 when the upper assembly is elevated by means of the drill pipe P, as for the purpose of pulling the apparatus from the well or for the purpose of elevating the bit B for rotation and orientation in the well.

When the valve means V is closed, it will be apparent piston 76 is free to flow therethrough into the cylinder bore above the piston 76 thereby permitting the upper assembly to drop relative to the lower assembly and to a position where the striker surface 63 on the mandrel strikes the stop surface 51 at the upper end of the lower assembly.

When the upper assembly is elevated or jacked up, the servo-piston is urged upwardly and seats upon the downwardly disposed bottom 71 or stop surface in the piston bore 65. Upon downward shifting of the upper assembly the piston 70 remains at the top of the bore 65. When the upper assembly reaches its lowermost position and the striker surfaces 63 strikes and stops against the stop surface 51, the valve members 90, in their down or open position meet the top surface 100 of a spring loaded stop plate 101 arranged in the lower end of the cylinder bore. Fluid flowing through the mandrel then enters the piston bore above the servo-piston 70 and urges the servo-piston downwardly, urging the drive piston with the valve, downwardly against the stop plate 101.

It is to be noted that a pressure drop in fluid pressure,

due to the friction loss, occurs between the upper and lower ends of the wash pipe and that the effective crosssectional area of the servo-piston is such that when acted upon by the greater fluid pressure at the upper end of the wash pipe, greater motive force is created than is created by the spring 97 and lesser fluid pressure at the lower end of the wash pipe acting upon the lower end of the drive piston when the valves are opened and the effective cross-sectional area of the drive piston is reduced or less than when the valves are closed. Accordingly, the servopiston is effective to urge the drive piston downwardly. When the valve members are in their closed position, the effective cross-sectional area of the drive piston is materially increased and the action of the servo piston is overcome.

Downward shifting of the stop plate 101 occurs when, as a result of wear, or the like, the upper assembly ove-rtravels on its downward stroke or a piece of foreign matter occurs between the drive piston and the plate which would create the effect of over-travel. Such shifting compresses the spring 102.

Suitable stop means 103 is provided to limit movement of the plate and prevent the plate from becoming displaced.

In the case illustrated, the stop plate 101 is a simple disc-shaped member slidably engaged in the cylinder bore and has a downwardly projecting cylindrical boss 105 with an annular radially outwardly opening groove 106 and a central flow passage 107. The boss 105 is slidably engaged in an upwardly opening cup-shaped like carrier 103 seated in the bottom of the cylinder bore. The side wall of the carrier 108 carries a pair of radially inwardly projecting stop pins 109, which pins project into the groove 106. The spring 102 is arranged within the cup to occur between the bottom of the boss 105, and the bottom 110 of the carrier. The bottom of the carrier is shown provided with an upwardly projecting boss 111 with a central flow passage 112, which passage allows for the free flow of circulating fluid through the tool and into the bit.

In practice, the stop plate 101 and its related parts, 102, 108, and 109, can be dispensed with or eliminated and closing of the valve effected by movement of the piston and valve members downwardly into engagement with the top of the box member 40. The primary purpose of the plate 101 and its related parts is to provide means to prevent possible hammering of and damage to the valve means when the valves are urged closed.

In practice and as illustrated in the drawings, the portion of the wash pipe between the stop collar 86 and the piston head 70 and which moves through the opening 47 in the collar 46 is splined, and the opening 47 is splined, so that the wash pipe and the structure carried by it will not rotate. This is desired so that the O-ring seals on the piston heads are not subject to torsional forces and wear and so that the valve members 90 and the upper ends of the pins 93 are not subjected to torsional forces when urged into engagement with those opposing parts with which they are related and which might damage them.

With the construction set forth above, it will be apparent that when our apparatus is arranged in a well as illustrated and the weight of the drill pipe P is exerted upon the apparatus to prevent the operation of the jack tool J, fluid can be circulated through the apparatus and the apparatus can be rotated to effect normal rotary drilling of the well. It will be further apparent that by elevating the drill pipe P sufficiently to extend the sub S and release the weight of the drill pipe from the remainder of the apparatus, and by continuing to conduct circulating fluid through the apparatus under pressure, the jack means will repeatedly jack up the collar C and permit it to drop and impart impact forces downwardly through the bit, which hit remains seated on the bottom of the Well whereby percussion drilling of new well hole is effected. At the same time circulating fluid continues to flow i the bit. In point of fact, when the collar drops, the pressure on the fluid flowing through the bit is increased slightly to enhance the effectiveness of the jet of fluid in reducing the formation.

When the above described apparatus is being used, percussion drilling can be employed or discontinued at any time and normal drilling operations resumed by rotating the apparatus.

When it is desired to change the direction and/ or drift angle of the hole being drilled, rotary drilling is discontinued, the bit is oriented in the desired direction by conventional methods, and percussion drilling is employed to start the hole on the desired course. When this has been accomplished, percussion drilling is discontinued and rotary drilling is resumed without removing the jack tool from the hole.

The apparatus described above is not limited to the drilling of slant on deviated holes. It can also be used advantageously for drilling vertical holes and for certain types of fishing operations. In addition, it can he used as a combination percussion and rotary drilling apparatuS.

Since the bit, in the above situation does not move out of contact with the formation, it will not shift or move out of proper and desired orientation, as would be the case if the bit was elevated and torsional forces in and through the apparatus were permitted free play.

It is important to note that the servo or pump down piston at the top of the wash pipe serves to complete closing of the valves, relatively slowly, after the impact generated by the tool has been imparted onto and through the bit. Slamming of the valves closed at the instant of impact would otherwise create a hydraulic shock or water hammer, that would act upwardly to counteract the downward force of impact and also possibly damage the valves.

While friction loss through the wash will create a certain pressure loss and differential between the pressures at the pump down piston and drive piston, such loss may not be adequate. Accordingly, a change in velocity of the fluid flowing through the wash pipe to further lower the pressure at the drive piston is provided for. Such change in velocity and resetting pressure differential is effected by establishing the flow passage through the wash pipe smaller than opening above the pump down piston, that is, the opening in the stop ring 67, or the flow passage 61 in the mandrel of the ring 67 is not pro vided. The positive pressure increase thus achieved at the pump down piston is adequate to overcome the resistance of the spring 97.

Having described only a typical preferred form and application of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any modifications and/or variations that may appear to those skilled in the art and which fall within the scope of the following claims.

Having described our invention, we claim:

1. A well drilling apparatus of the character referred to including, an elongate string of fluid conducting drill pipe extending downwardly into a well structure, an elongate fluid conducting rotary drive axially extensible sub fixed to the lower end of the string of drill pipe, an elongate fluid conducting collar fixed to and depending from the sub, an elongate fluid conducting jack tool fixed to and depending from the lower end of the drill collar and a formation engaging bit fixed to the lower end of the jack tool, said jack tool being driven by fluid conducted through the apparatus and adapted to elevate the drill collar relative to the bit and drill pipe string, to permit the drill collar to drop and to stop downward movement of the drill collar to direct impact forces onto and through the bit.

2. An apparatus as set forth in claim 1, wherein said bit is a rotary cone bit and has a fluid passage communicating with the pack tool and a nozzle communicating with the fluid passage to direct a jet of fluid onto the formation in advance of and to one side of the bit.

3. An apparatus as set forth in claim 1, wherein said jack tool includes an upper assembly fixed to and depending from the drill collar and a lower assembly fixed to and projecting upwardly from the bit, said upper assembly including an elongate splined mandrel with a head at its upper end to connect with the drill collar and defining a downwardly disposed striker surface, an elongate wash pipe coupled to and depending from the mandrel and an enlarged piston with a central flow passage on the lower end of the wash pipe, said lower assembly including an elongate splined barrel slidably receiving the mandrel and having an upwardly disposed stop surface opposing the striker surface, an elongate cylinder with closed upper and lower ends, and opening in the upper end of the cylinder to slidably receive the wash pipe, the lower end of the cylinder having a central flow passage and threadedly coupled with the bit, the upper end portion of the cylinder having a port communicating between the exterior and the interior of the cylinder, said piston slidably engaged in the cylinder, said piston having axially extending flow ports communicating with the cylinder above and below the piston, valve means to open and close the ports in the piston and actuating means related to the valve means to close said valve means when the piston is moved into the lower portion of the cylinder and to open said valve means when the piston is moved into the upper portion of the cylinder.

4. An apparatus as set forth in claim 1, wherein said jack tool includes an upper assembly fixed to and depending from the drill collar and a lower assembly fixed to and projecting upwardly from the bit, said upper assembly including an elongate splined mandrel with a head at its upper end to connect with the drill collar and defining a downwardly disposed striker surface, an elongate wash pipe coupled to and depending from the mandrel and an enlarged piston with a central fiow passage on the lower end of the wash pip-e, said lower assembly including an elongate splined barrel "slidably receiving the mandrel and having an upwardly disposed stop surface opposing the striker surface, an elongate cylinder with closed upper and lower ends, an opening in the upper end of the cylinder to slidably receive the wash pipe, the lower end of the cylinder having a central flow passage and threadedly coupled with the bit, the upper end portion of the cylinder having a port communicating between the exterior and the interior of the cylinder, said piston slidably engaged in the cylinder, said piston having axially extending flow ports communicating with the cylinder above and below the piston, valve means to open and close the ports in the piston and actuating means related to the valve means to close said valve means when the piston is moved into the lower portion of the cylinder and to open said valve means when the piston is moved into the upper portion of the cylinder, said bit being a rotary cone bit and having a fluid passage communicating with the jack tool and a downwardly and laterally directed nozzle communicating with the fluid passage to direct a jet of fluid onto the formation in advance of and to one side of the bit.

5. An apparatus as set forth in claim 1, wherein said jack tool includes an upper assembly fixed to and depend ing from the drill collar and a lower assembly fixed to and projecting upwardly from the bit, said upper assembly including an elongate splined mandrel with a head at its upper end to connect with the drill collar and defining a downwardly disposed striker surface, an elongate wash pipe coupled with and depending from the mandrel and an enlarged piston with a central flow passage on the lower end of the wash pipe, said lower assembly including an elongate upper splined barrel slidably receiving the mandrel and having an upwardly disposed stop surface opposing the striker surface, an elongate lower cylinder with closed upper and lower ends, an opening in the upper end of the cylinder to slidably reccive the wash pipe, the lower end of the cylinder having a central flow passage and threadedly coupled with the bit, the upper end portion of the cylinder having a port communicating between the exterior and the interior of the cylinder, said piston slidably engaged in the cylinder, said piston having axially extending flow ports cornmunicating with the cylinder above and below the piston, valve means to open and close the ports in the piston and actuating means related to the valve means to close said valve means when the piston is moved into the lower portion of the cylinder and to open said valve means when the piston is moved into the upper portion of the cylinder, said valve means including annular valve seats in the lower ends of the ports in the pistons, valve members below the piston and shiftable vertically into and out of engagement in the seats, elongate stems on the valve members projecting upwardly and freely through said flow ports and terminating above the piston, and latch means engageable with the stems and adapted to releasably hold the valve members in their open and closed positions, the valve members being adapted to stop against the bottom of the cylinder to release the latch means and to effect closing of the valves as the piston moves into the lower portion of the cylinder when said members are in their open position, the stems being adapted to stop against the top of the cylinder to release the latch means and to effect opening of the valves as the piston moves into the upper position of the cylinder, when the valves are in their closed positions.

6. An apparatus as set forth in claim 1 wherein said jack tool includes an upper assembly fixed to and depending from the drill collar and a lower assembly fixed to n and projecting upwardly from the bit, said upper assembly including an elongate splined mandrel with a head at its upper end to connect with the drill collar and defining a downwardly disposed striker surface, an elongate wash pipe coupled to and depending from the mandrel and an enlarged piston with a central flow passage on the lower end of the wash pipe, said lower assembly including an upper elongate splined barrel slidably receiving the mandrel and having an upwardly disposed stop surface opposing the striker surface, an elongate lower cylinder with closed upper and lower ends, an opening in the upper end of the cylinder to slidably receive the wash pipe, the lower end of the cylinder having a central flow passage and coupled with the bit, the upper end portion of the cylinder having a port communicating between the exterior and the interior of the cylinder, said piston slidably engaged in the cylinder, said piston having axially extending flow ports communicating with the cylinder above and below the piston, valve means to open and close the ports in the piston and actuating means related to the valve means to close said valve means when the piston is moved into the lower portion of the cylinder and to open said valve means when the piston is moved into the upper portion of the cylinder, said valve means including annular valve seats in the lower ends of the ports in the pistons, valve members below the piston and shiftable vertically into and out of engagement in the seats, elongate stems on the valve members projecting upwardly and freely through said flow ports and terminating above the piston, and latch means engageable with the stems and adapted to releasably hold the valve members in their open and closed positions, the valve members being adapted to stop against the bottom of the cylinder, to release the latch means and effect closing of the valves as the piston moves into the lower portion of the cylinder when said members are in their open position, the stems being adapted to stop against the top of the cylinder to release said latch means and to effect opening of the valves as the piston moves into the upper portion of the cylinder, when the valves are in their closed positions, said actuating means including 12 spring means related to the stems and biased when the valve members are in their opened positions and adapted to urge the valve members up to their closed positions when the latch means are released.

7. A hydraulically operated jack tool to be engaged between upper and lower portions of an elongate, vertical fluid conducting well drilling string and operable to reciprocate the lower portion of the string relative to the upper portion of the string, said jack tool including an upper assembly to be fixed to and depending from the upper portion of the string and a lower assembly fixed to and projecting upwardly from the lower portion of the string, said upper assembly including an elongate fluid splined mandrel with a head at its upper end to connect with the upper portion of the string and defining a downwardly disposed striker surface, an elongate vertical wash pipe coupling means between the upper end of the wash pipe and the lower end of the mandrel and an enlarged piston with a central flow passage on the lower end of the wash pipe, said lower assembly including an elongate splined upper barrel slidably receiving the mandrel and having an upwardly disposed stop surface opposing the striker surface, an elongate lower cylinder with closed upper and lower ends, an opening in the upper end of the cylinder to slidably receive the wash pipe, the lower end of the cylinder having a central flow passage and coupled with the lower section of the string, the upper end portion of the cylinder having a port communicating between the exterior and the interior of the cylinder, said piston slidably engaged in the cylinder, said piston having axially extending fiow ports communicating with the cylinder above and below the piston, valve means to open and close the ports in the piston and actuating means related to the valve means to close said valve means when the piston is moved into and reaches the lower portion of the cylinder after the striker surface engages the stop surface and to open said valve means when the piston is moved into and reaches the upper portion of the cylinder.

8. A structure as set forth in claim 7 wherein said coupling means between the wash pipe and mandrel includes an elongate cylinder bore entering the lower end of the mandrel, an enlarged pump down piston on the upper end of the wash pipe and slidably engaged in the cylinder bore and an annular retainer ring engaged about the upper portion of wash pipe and engaged in the lower end of the cylinder bore.

9. A structure as set forth in claim 7 wherein said coupling means between the wash pipe and mandrel includes an elongate cylinder bore entering the lower end of the mandrel, an enlarged pump down piston on the upper end of the wash pipe and slidably engaged in the cylinder bore and an annular retainer ring engaged about the upper portion of wash pipe and engaged in the lower end of the cylinder bore, said valve means including annular valve seats in the lower ends of the ports in the pistons, valve members below the piston and shiftable vertically into and out of engagement in the seats, elongate stems on the valve members projecting upwardly and freely through said flow ports and terminating above the piston, and latch means engageable with the stems and adapted to releasably hold the valve members in the opened and closed positions, the valve members being adapted to stop against the bottom of the cylinder to release the latch means and effect closing of the valve as the piston moves into the lower portion of the cylinder when said members are in their open position, the stems being adapted to stop against the top of the cylinder to release the latch means and effect opening of the valves as the piston moves into the upper position of the cylinder, when the valves are in their closed positions.

10. A structure as set forth in claim 7 wherein said coupling means between the wash pipe and mandrel includes an elongate cylinder bore entering the lower end of the mandrel, an enlarged pump down piston on the upper end of the wash pipe and slidably engaged in the cylinder bore and an annular retainer ring engaged about the upper portion of wash pipe and engaged in the lower end of the cylinder bore, said valve means including annular valve seats in the lower ends of the ports in the pistons, valve members below the piston and shiftable vertically into and out of engagement in the seats, elongate stems on the valve members projecting upwardly and freely through said flow ports and terminating above the piston, and latch means engageable with the stems and adapted to releasably hold the valve members in the opened and closed positions, the valve members being adapted to stop against the bottom of the cylinder to release the latch means and effect closing of the valve as the piston moves into the lower portion of the cylinder when said members are in their open position, the stems being adapted to stop against the top of the cylinder to release the latch means and effect opening of the valves as the piston moves into the upper position of the cylinder, when the valves are in their closed positions, and actuating means including spring means related to the stems and biased when the valve members are in their closed positions and adapted to urge the valve members to their open positions after the piston reaches to the upper portion of the cylinder and the latch means are released.

11. A structure as set forth in claim 7 wherein said coupling means between the wash pipe and mandrel includes an elongate cylinder bore entering the lower end of the mandrel, an enlarged pump down piston on the upper end of the wash pipe and slidably engaged in the cylinder bore and an annular retainer ring engaged about the lower portion of wash pipe and engaged in the lower end of the cylinder bore, said valve means including annular valve seats in the lower ends of the ports in the pistons, valve members below the piston and shiftable vertically into and out of engagement in the seats, elongate stems on the valve members projecting upwardly and freely through said flow ports and terminating above the piston, and latch means engageable with the stems and adapted to releasably hold the valve members in the opened and closed positions, the valve members being adapted to stop against the bottom of the cylinder to release the latch means and eifect closing of the valve as the piston moves into the lower portion of the cylinder when said members are in their open position, the stems being adapted to stop against the top of the cylinder to release the latch means and effect opening of the valves as the piston moves into the upper position of the cylinder, When the valves are in their closed positions, and actuating means including spring means related to the stems and biased when the valve members are in their closed positions and adapted to urge the valve members to their open positions after the piston reaches to the upper portion of the cylinder and the latch means are released, said actuating means including a stop on the wash pipe above the piston and below the upper ends of the stems, stops on the stems above the piston and below the stop on the wash pipe and a compression spring between and acting upon the stops on the stems and the stop on the wash pipe.

12. A structure as set forth in claim 7 wherein said coupling means between the wash pipe and mandrel includes an elongate cylinder bore entering the lower end of the mandrel, an enlarged pump down piston on the upper end of the wash pipe and slidably engaged in the cylinder bore and an annular retainer ring engaged about the upper portion of wash pipe and engaged in the lower end of the cylinder bore, said valve means including annular valve seats in the lower ends of the ports in the pistons, valve members below the piston and shifts.- ble vertically into and out of engagement in the seats, elongate stems on the valve members projecting upwardly and freely through said flow ports and terminating above the piston, and latch means engageable with the stems and adapted to releasably hold the valve members in the opened and closed positions, the valve members being adapted to stop against the bottom of the cylinder to release the latch means and effect closing of the valve as the piston moves into the lower portion of the cylinder when said members are in their open position, the stems being adapted to stop against the top of the cylinder to release the latch means and effect opening of the valves as the piston moves into the upper position of the cylinder, when the valves are in their closed positions, and actuating means including spring means related to the stems and biased when the valve members are in their closed positions and adapted to urge the valve members to their open positions after the piston reaches to the upper portion of the cylinder and the latch means are released, and resilient stop means at the lower end of the cylinder to occur between the bottom of the cylinder and the valve members to effect closing of the valve members without damage to said members when the piston reaches the lower portion of the cylinder, said resilient stop means including an annular stop member shiftably engaged in the cylinder and engageable with said valve members and a compression spring between said stop member and the bottom of the cylinder, said compression spring affording greater resistance than the latch means.

References Cited UNITED STATES PATENTS 1,693,017 11/1928 Bartholomae -321 1,867,833 7/1932 Hill 175--321 X 2,100,420 11/1937 Wright 175-306 X 2,873,092 2/1959 DWyer 17561 2,901,221 8/1959 Whittle 175-321 X 2,953,351 9/1960 Bodine 175-56 3,200,895 8/1965 Womack 175306 X NILE C. BYERS, JR., Primary Examiner. 

